Question: Which archaeological site was the former capitol of the Achaemenid Empire?
Paraphrase: Which archeological site was the Achaemenid Empire's former capital?
SPARQL (Wikidata):  select distinct ?obj where { wd:Q389688 wdt:P36 ?obj . ?obj wdt:P31 wd:Q839954 } 
Answer: Persepolis, Susa, Pasargadae, Ecbatana